1. Field of the Invention
The present invention relates to a procedure and device for the assembly of the ends of optical fibers arranged in the form of a sheet and, more specifically, to such a procedure and such a device that allow the assembly of such fiber sheets in order to connect them to integrated optical components.
2. Description of the Prior Art
Such components include waveguides integrated in a substrate, for which the ends of these waveguides need to be connected to optical fibers. For example, a coupler with m inputs and n outputs is connected to sheets of fibers that contain m fibers and n fibers, respectively. In accordance with a first procedure used to achieve this connection, the axis of the end of each fiber is attached and aligned, by micromanipulation, with the axis of the end of the corresponding waveguide, and the respective positions of these ends are stabilized with the aid of an adhesive product.
This procedure, which requires the micromanipulation of each of the fibers, is obviously a long and therefore costly procedure.
In order to speed up the connection operations, it has been proposed that the corresponding ends of a fiber sheet be unified beforehand, in accordance with a configuration that conforms to the configuration of the ends of the waveguide in the integrated optical component, and then connecting simultaneously, by means of a single glueing operation, the ends of the fibers and the corresponding guides.
This proposal raises the difficulty of the preceding unification of the ends of the fibers, in such a way that these ends are aligned in a rectilinear way in accordance with a positioning arrangement that is not subject to deformation, with a spacing that is consistent with that of the ends of the waveguides to which the ends of the fibers are to be connected.
For this purpose, it has been proposed that these ends be positioned in parallel grooves in a substrate, with the spacing of these grooves being identical to that of the ends of the waveguides. In this context, a substrate with grooves that have a V-shaped cross section is known, in which each fiber rests against the two sides of the groove that receives it, with the overall assembly of these grooves being covered by a plate glued to the substrate in contact with the fibers.
This structure allows the desired rapid assembly to be obtained. However, it has the disadvantage of being hyperstatic as soon as is used to assemble more than two fibers. The presence of a parasitic particle between a fiber and one side of a groove, or between a fiber and the plate, can then interfere with the perfect alignment of the ends of the fibers in the sheet thus formed. A fault in the alignment of any one of the fibers also perturbs equally the alignment of the other fibers. With fiber sheets assembled in this way, the manufacturing defect rate is high, with a resulting increase in manufacturing costs.
Consideration has also been given to the idea of guiding the fibers through aligned circular channels in a single substrate, then immobilizing the fibers in these channels through the application of an adhesive. Unfortunately, because the diameter of such channels must be larger than that of the fibers, such an assembly is necessarily hypostatic. Consequently, neither the alignment nor the coplanarity of the assembled fibers can be ensured.
The use has also been proposed of substrates with grooves that have an essentially rectangular cross section, at the bottom of which the fibers are affixed by glueing. In this case, the grooves must be significantly wider than the diameter of the fibers, in order to allow the fibers to be applied against the bottom of the grooves, to the detriment of the transverse guiding of the fibers. Furthermore, a parasitic particle located between a fiber and the bottom of a groove can cause the pivoting of a pressure plate on the portion of the fiber that is located outside the groove, to the detriment of the regularity of the embedding of the other fibers in their respective grooves.